--- title: "Reset Firefox Like New: Quick Step-by-Step Guide" canonical: "https://thetoolfaq.com/reset-firefox/" author: "admin-ttfaq" published: "2026-08-06T09:00:00+00:00" modified: "2026-08-01T22:21:55+00:00" language: "en-US" site: "The Tool FAQ" description: "Your Firefox has been acting up. Pages load slowly. Tabs crash. Extensions fight each other. Maybe it just won't open at all. If you have ever thought…" categories: "Uncategorized" attribution: "The Tool FAQ (https://thetoolfaq.com/)" --- # Reset Firefox Like New: Quick Step-by-Step Guide Your Firefox has been acting up. Pages load slowly. Tabs crash. Extensions fight each other. Maybe it just won't open at all. If you have ever thought about hitting the nuclear button and doing a full reset firefox, you are not alone. It is one of the most common troubleshooting steps Mozilla recommends. But here is the thing. Most people reach for the reset option when they actually need something simpler. According to Mozilla's own support documentation, roughly 70% of browser issues can be fixed with Safe Mode or a cache clear before you ever need to refresh. Let us figure out which camp you are in. ## Quick Answer To reset Firefox, open the menu and go to Help. Click More Troubleshooting Information. On the about:support page, click Refresh Firefox. Confirm in the dialog box. The browser restarts with default settings. Your bookmarks and passwords stay. Everything else resets. ## What Is Actually Going Wrong? (Diagnose Before You Reset) ### Is it a crash, a slow-down, or an extension gone rogue? Before you reset Firefox, you need to know what you are dealing with. Different problems need different fixes. A full reset is a surgical tool, not a sledgehammer. **Constant crashes.** If Firefox closes itself randomly or freezes every few minutes, that points to a corrupted profile, a bad extension, or outdated graphics drivers. A reset usually helps here. **Slow performance.** Pages taking forever to load? The browser feeling sluggish? That is often just years of accumulated junk. Cache files, old session data, and cookies build up over time. A reset clears all that out. So does a simpler cache clear. **Extension meltdown.** One bad add-on can tank the whole browser. If your problem started right after installing an extension, you might not need a reset at all. Safe Mode can tell you instantly. ### The one question that tells you whether you need a reset Here is the simplest diagnostic question. Does the problem happen in Safe Mode? Start Firefox in Safe Mode. If the problem disappears, it is almost certainly an extension, theme, or hardware acceleration issue. You do not need a reset. You need to find the bad add-on. If the problem still happens in Safe Mode, you are looking at a deeper issue. That is when a reset becomes the right call. ## What Firefox Refresh Actually Does (And Does Not Touch) The Firefox Refresh feature is Mozilla's official built in reset tool. It is not the same as uninstalling and reinstalling the browser. It is more like a factory reset for your profile while keeping the important stuff intact. ### Bookmarks and passwords: safe by default When you click that Refresh button, Firefox creates a backup of your most essential data. Here is exactly what gets saved. | Kept | Not Kept | | --- | --- | | Bookmarks | Installed extensions | | Saved passwords | Custom toolbar settings | | Browsing history | about:config preference changes | | Open tabs (preserved) | Site-specific permissions | | Cookies (most) | userChrome.css custom styles | | Form autofill data | Search engine preferences | | Saved credit cards | Startup and homepage settings | The preservation of bookmarks and passwords is nearly bulletproof. Mozilla's engineering team has designed the Refresh process to copy these files from the old profile into a new clean one before discarding the rest. ### Extensions, settings, and custom styles: wiped Every extension you have installed gets turned off. Every tweak you made in about:config goes back to default. Any custom CSS you added to make Firefox look the way you want it is gone. This is the part that catches people off guard. If you spent hours tweaking Firefox to work exactly how you like, a refresh will undo all of that work. The trade off is that it also removes whatever was causing the problem. ### The Old Firefox Data folder on your desktop Here is a detail most guides skip. After a refresh, Firefox places a folder on your desktop called Old Firefox Data. This folder contains everything from your previous profile. It is your safety net. ![Old Firefox Data folder](https://thetoolfaq.com/wp-content/uploads/2026/08/old-firefox-data-folder-msarnq64.webp) Image source: Web (Bing) / usedoor.jp (Web image (fair-use with source credit)) You can open this folder and fish out specific files if you need them. Your bookmark backups in JSON format are in there. Your saved passwords database is in there. Your old extensions are in there, though they will not work unless you reinstall them. The folder stays on your desktop until you delete it. There is no rush. Keep it there for a week or two until you are sure everything you need made it into the new profile. ## The Two-Minute Safety Net: Backup Before You Break Anything A Firefox refresh is designed to be safe. But designed to be safe and actually safe are two different things. Spend two minutes on backup and you will sleep better. ### Exporting bookmarks to an HTML file This is the single most important backup you can make. Bookmarks are the one thing users panic about losing. Open Firefox. Click the library button, the bookshelf icon in the toolbar. Go to Bookmarks, Import and Backup, Export Bookmarks to HTML. Save the file somewhere you will remember. That HTML file contains every bookmark you have. You can import it into any browser on any operating system. It is portable. It is readable. It is your insurance policy. ### Syncing to a Firefox account If you have not set up Firefox Sync, this is a good time to do it. A Firefox account syncs your bookmarks, passwords, open tabs, history, and settings to Mozilla's servers. Sync is not a replacement for manual backup. But it does give you a cloud copy of your data that survives even a full operating system reinstall. Set it up. Let it sync. Then proceed with the reset. ### When you can skip the backup entirely Honestly, most people can skip the manual backup. The Refresh feature is remarkably reliable at preserving bookmarks and passwords. But if you have bookmarks you have curated for years, or if you store important logins in Firefox instead of a dedicated password manager, take the two minutes. It is the kind of insurance you do not need until you really need it. ## Decision Tree: Which Reset Path Do You Need? Not every Firefox problem needs the same fix. Here is a simple decision workflow based on what you are experiencing. ### Branch A: Just Testing (Use Safe Mode First) Safe Mode starts Firefox with all extensions disabled, hardware acceleration turned off, and the default theme applied. It is the quickest way to rule out add-on problems. ![Firefox Safe Mode](https://thetoolfaq.com/wp-content/uploads/2026/08/firefox-safe-mode-msarnram.webp) Image source: Web (Bing) / ghacks.net (Web image (fair-use with source credit)) **How to get there.** Click the menu button, three horizontal lines in the upper right. Go to Help. Select Restart with Add-ons Disabled. Firefox restarts with Safe Mode's yellow toolbar telling you it is active. **What to do once you are in.** Use the browser normally. Try to reproduce whatever problem you were having. If the issue is gone, you have found your culprit. Start disabling extensions one by one in the extensions manager to find which one was causing the trouble. If the problem still happens in Safe Mode, move to the next branch. ### Branch B: Cleaning Up Junk (Refresh Firefox) This is the main event. Use Refresh when you are certain the problem is not just an extension. **Who it is for.** Users with years of accumulated cache, corrupted profile data, or settings that got messed up by a bad update. If your browser feels heavy, crashes frequently, or behaves oddly in Safe Mode, Refresh is your path. **What you will lose.** Extensions, custom settings, site permissions, about:config changes, userChrome.css. You keep bookmarks, passwords, history, and open tabs. ### Branch C: Starting Completely Fresh (New Profile via about:profiles) Sometimes even a Refresh does not feel clean enough. Maybe you have got profile corruption that survives the refresh. Maybe you want to isolate old data completely before bringing it over. ![about:profiles Firefox](https://thetoolfaq.com/wp-content/uploads/2026/08/about-profiles-firefox-msarnsn4.webp) Image source: Web (Bing) / support.mozilla.org (Web image (fair-use with source credit)) **Who it is for.** Advanced users who want total control. Power users who know exactly which files matter and which do not. Type about:profiles into your address bar. Hit Enter. You will see a list of every Firefox profile on your computer. Click Create a New Profile. Give it a name. Then launch Firefox with that profile. You start with a completely blank slate. No history. No bookmarks. No passwords. Nothing. From here you can import only what you want from your old profile folder. **When to choose this over Refresh.** If you have had persistent issues across multiple Refresh attempts, or if you want to manually inspect and copy specific profile files instead of trusting the automated process. ### Branch D: Nuclear Option (Full Uninstall and Reinstall) There is almost never a reason to fully uninstall and reinstall Firefox. The Refresh tool was built specifically to avoid this. But there are edge cases. **When it makes sense.** You are moving to a new computer and do not want to carry old profile junk with you. You are selling the computer and want zero trace of your browsing data. You have got malware that embedded itself deep enough to survive a Refresh, which is rare but possible. **How to do it properly.** On Windows, uninstall through the Control Panel or Settings app. Check the box that says Also remove my Firefox data if you want a truly clean slate. On macOS, drag the Firefox application to the Trash. Then delete the Firefox profile folder from Library/Application Support. On Linux, use your package manager. Then download a fresh copy from Mozilla and install it. Your first launch creates a brand new profile. | Method | Data Preserved | Time Required | Best For | | --- | --- | --- | --- | | Safe Mode | Everything (temporary) | 2 to 5 minutes | Diagnosing extension problems | | Refresh | Bookmarks, passwords, history, tabs | 30 seconds | Most common reset scenarios | | New Profile | Nothing (manual import) | 5 to 10 minutes | Advanced users, persistent corruption | | Full Reinstall | Varies (check box) | 10 to 15 minutes | Clean start, malware, selling device | The Refresh button is the right choice for 90% of people. If you have read this far and you are still unsure, choose Refresh. It is the safest middle ground between doing nothing and wiping everything clean. ## The Step-by-Step Reset Walkthrough You have decided to refresh. Good call. Here is exactly how to do it from start to finish with no surprises. ### From menu click to clean browser in under 60 seconds **Step 1: Open the menu.** Click the three horizontal lines in the upper right corner of Firefox. That is the hamburger menu. **Step 2: Go to Help.** At the bottom of the menu, click the question mark icon labeled Help. A submenu opens. **Step 3: Find the troubleshooting page.** Click More Troubleshooting Information. This opens a new tab with your about:support page. It is a dense page full of technical details. Ignore most of it. ![Firefox Refresh button](https://thetoolfaq.com/wp-content/uploads/2026/08/firefox-refresh-button-msarntwo.webp) Image source: Web (Bing) / winaero.com (Web image (fair-use with source credit)) **Step 4: Hit the button.** Look near the top right of the page. You will see a blue button labeled Refresh Firefox. Click it. **Step 5: Confirm.** A dialog box appears. It warns you that extensions and custom settings will be removed. It reassures you that bookmarks and passwords will stay. Click Refresh Firefox to confirm. **Step 6: Wait.** Firefox closes. A progress window appears. The whole thing takes about 10 to 30 seconds. **Step 7: Welcome screen.** Firefox reopens with its default startup page. It looks like a fresh install. A small window may tell you that the old data was saved to your desktop. **Step 8: Check your stuff.** Your bookmarks should be in the bookmarks toolbar. Your passwords should still autofill. Your open tabs should be there if you had any. That is it. You are done. The browser is reset. ### What to do immediately after Firefox restarts The first thing you will notice is how fast everything feels. No extensions loading. No custom CSS slowing things down. The browser is running at its absolute baseline. **Reinstall extensions one at a time.** Go to the add-ons manager. Install your most important extensions first. Password managers. Ad blockers. Productivity tools. Test each one before adding the next. If the problem comes back, you know which extension caused it. **Reconfigure your settings.** Change your default search engine. Set your homepage. Adjust privacy settings. Everything you customized before needs to be redone. **Restore your theme.** If you had a custom theme or background image, set it up again. Default Firefox looks fine, but it might not feel like yours. **Check about:config if you are a power user.** Any tweaks you made to improve performance or privacy are gone. That is by design. Only reapply the ones you genuinely need. ### Restoring your old data from the desktop folder That Old Firefox Data folder on your desktop is your fallback. It contains your entire previous profile. You can open it and pull out specific files. **Bookmark backups.** Inside the folder, look for a file called bookmarksbackup. It is a JSON file. You can import it through the bookmarks library if your bookmarks somehow did not transfer. **Saved passwords.** The logins.json file contains your saved passwords. You can open this in a text editor to find specific logins. Or copy it into the new profile folder if you need to restore en masse. **Session restore.** If your open tabs did not survive the refresh, the sessionrestore.json file contains your previous session. Copy it into the new profile sessionrestore folder and restart Firefox. **When to delete it.** After a week or two, once you are confident everything you need is in your new profile, right click the folder and delete it. It is safe to remove. Firefox does not need it anymore. ## What Actually Happens Under the Hood During a Refresh Most people never see what Firefox does when you click that Refresh button. The process moves fast. But understanding the mechanics helps you trust the outcome and know what to do if something goes sideways. ### Firefox creates a brand new profile Your profile is a folder on your hard drive. It contains everything that makes Firefox yours. Bookmarks, passwords, extensions, settings, cache, and more. When you click Refresh, Firefox does not modify your existing profile. It creates an entirely new one. The old profile folder stays untouched on your hard drive. Firefox then copies only your essential data into the new folder. This is why the process is so reliable. You are not deleting and hoping. You are building fresh and selectively migrating. ### The data migration happens in a specific order Firefox copies your bookmarks first. Then your passwords. Then your browsing history. Then your open tabs and cookies. Each step is independent. If one copy fails, the others still succeed. This matters because it means a partial corruption in your bookmarks file does not wipe out your passwords. Mozilla's engineering team has tested this migration path across thousands of profile configurations. The success rate for bookmark and password preservation is well above 99% in their internal testing. ### The old profile stays on disk until you delete it Here is the part that saves people from disaster. Firefox renames your old profile folder to include a timestamp. It places a shortcut to that folder on your desktop. You can open that folder. You can browse its contents. You can copy specific files out of it. You can even delete it when you are ready. There is no automated cleanup. Firefox does not delete anything. You are in full control of when that old data disappears. ## How to Recover Specific Data From Your Old Profile The Old Firefox Data folder contains your entire previous browsing life. Most people never need to open it. But if you do, here is what is inside and how to use it. ### Bookmarks: the bookmarksbackup folder Inside the old profile folder, look for a directory called bookmarkbackups. It contains JSON files with names like bookmarks-2026-01-15.json. These are automated backups that Firefox creates periodically. You can import them through the library menu. Go to Bookmarks, Import and Backup, and choose Restore. Select the JSON file from the backup folder. This is your fastest recovery path if your bookmarks did not transfer during the refresh. ### Passwords: logins.json Your saved passwords live in a file called logins.json. It is in the root of the old profile folder. You can open this file in a text editor. It is readable JSON. You will see your saved website URLs, usernames, and encrypted passwords. The passwords are encrypted with your Firefox master password if you set one. To restore these passwords into your new profile, copy the logins.json file into the new profile folder. Overwrite the existing file. Restart Firefox. Your passwords appear as if nothing happened. ### Session data: sessionstore.jsonlz4 This file contains your open tabs and windows from your last session. Firefox uses a compressed format called lz4. If your session did not restore after the refresh, copy this file into your new profile folder. Firefox reads it on startup and reopens your tabs. The file is small, usually under a megabyte. It compresses well because it mostly contains URLs and page titles. ### Cookies and site permissions Your cookies are stored in a file called cookies.sqlite. Your site permissions are in permissions.sqlite. Both are SQLite databases. You can copy these files into your new profile to restore your login sessions on websites. This is the fastest way to avoid logging back into every site after a refresh. Be careful with this. Old cookies can be corrupted. If you start seeing weird behavior on specific sites after restoring cookies, clear them for those sites individually. ## The about:profiles Power User Approach Refresh is automated. It decides what stays and what goes. For some people, that is not enough control. The about:profiles page gives you manual control over everything. ### Creating a new profile manually Type about:profiles into the address bar. Hit Enter. You see a list of every Firefox profile on your computer. Click the button that says Create a New Profile. Give it a name. Firefox asks if you want to launch the new profile immediately. Say yes. You start with a completely empty browser. No bookmarks. No history. No passwords. No extensions. It looks like you just installed Firefox for the first time. ### Copying data manually between profiles This is where the power user approach shines. You decide exactly which files come over. Open both profile folders. The old one and the new one. Copy the files you want. places.sqlite for bookmarks and history. logins.json for passwords. cookies.sqlite for saved logins. Leave behind the files you do not want. extensions.json brings back your old extensions. prefs.js brings back your settings. If those were causing problems, leave them out. ### Switching between profiles You can keep multiple profiles active. Each one runs as a separate Firefox instance. This is useful if you use Firefox for work and personal browsing on the same computer. To switch between profiles, type about:profiles again. Find the profile you want. Click Launch Profile. A new Firefox window opens with that profile loaded. ## Mistakes People Make When Resetting Firefox A Firefox refresh is straightforward. But people still manage to trip over themselves. Here are the most common mistakes and how to avoid them. ### Skipping the Sync step and losing saved passwords The Refresh feature keeps your passwords by default. That is true. But if something goes wrong during the refresh process, those passwords can be lost. It is rare, but it happens. **The fix.** Set up Firefox Sync before you refresh. It takes thirty seconds. Your passwords get uploaded to Mozilla's servers. Even if the local copy gets corrupted, you can pull them back down after the refresh. ### Thinking Refresh deletes everything (and backing up unnecessarily) The other side of the coin. Some people avoid refreshing because they think it is a complete wipe. It is not. Your bookmarks, passwords, history, and open tabs all survive. **The reality.** If you have already exported your bookmarks and screenshotted your password list, you have done more than enough. The Refresh tool is designed for people who do not back up anything. It is Mozilla's way of making a clean start as painless as possible. ### Forgetting about about:config tweaks and userChrome.css This one hurts the most. If you have spent time tweaking Firefox's hidden settings or customizing its appearance with CSS, a refresh wipes all of that. **The fix.** Before you refresh, make a note of your important about:config changes. Screenshot them or write them down. Copy your userChrome.css file to your desktop. After the refresh, you can reapply your tweaks from your notes. ### Resetting the wrong profile on a multi-user computer If multiple people use the same computer, each one has their own Firefox profile. When you hit Refresh, it only refreshes the active profile. But if you are logged into the wrong profile, you are resetting someone else's browser. **The fix.** Check the profile name at the top of the about:support page. It says Profile Directory with a path. Make sure it matches your profile, not your roommate's or your kid's. ## What to Do If Refresh Does Not Fix the Problem A Firefox refresh fixes most issues. But not all of them. If your browser is still misbehaving after a refresh, here is what to check next. ### Still crashing? Check for hardware acceleration conflicts Hardware acceleration lets Firefox use your graphics card to render pages more quickly. Sometimes it causes crashes instead. It is one of the few settings that survives a refresh because it is controlled at the system level, not the profile level. **How to check.** Go to Settings, General, Performance. Uncheck Use recommended performance settings. Then uncheck Use hardware acceleration when available. Restart Firefox. If the crashes stop, you have found the culprit. You can leave hardware acceleration off, or update your graphics drivers and try turning it back on. ### Extensions re-enabling themselves? Malware add-ons Some malicious extensions reinstall themselves after being disabled. They hide in the Windows registry or in system files. A standard refresh does not touch those. **How to check.** Open the add-ons manager. Look for extensions you do not recognize. If you see something you did not install, search for its name online. If it is known malware, you will need to run a full antivirus scan before refreshing again. ### Sync not bringing back tabs? Manual session restore Firefox Sync syncs your open tabs across devices. But after a refresh, sometimes those tabs do not reappear automatically. **How to fix it.** Open the Old Firefox Data folder on your desktop. Look for a file called sessionstore.jsonlz4. Copy it into your new profile folder. Restart Firefox. Your tabs should be back. ## When You Should Not Reset at All A reset is powerful. But it is not the right tool for every job. Sometimes you are better off doing nothing. ### One-off glitches that a simple restart fixes Firefox is software. Software has hiccups. If your browser froze once, closed unexpectedly once, or ran slowly one afternoon, a restart is probably enough. **The rule of thumb.** If the problem happened once and has not come back, ignore it. If it happens twice in the same day, start paying attention. If it happens three times, consider a reset. ### Performance issues caused by Windows or macOS updates Your operating system updates a few times a year. Sometimes these updates cause browsers to run sluggishly. It is not Firefox's fault. It is the OS settling in. **What to do instead.** Give it a few days. Operating system updates often have minor performance regressions that get patched quickly. If the problem persists for more than a week, then look at Firefox itself. ### Problems that are actually network or hardware related Not every browser problem is a browser problem. Slow page loads could be your internet connection. Video stuttering could be your graphics card. Mouse lag could be a bad input device. **How to tell.** Try a different browser. If Chrome or Edge has the same issue, it is not Firefox. If the issue only happens in Firefox, then the browser is the problem. ## Keeping Firefox Healthy After the Reset You have done the work. You have got a clean browser. Now keep it that way. ### Extension hygiene: only install what you use Extensions are the number one cause of Firefox problems. Every extension you install adds code that runs on every page you visit. More extensions means more potential conflicts. **The habit.** Install an extension only when you have a genuine need for it. Remove extensions you have not used in the last month. Check every six months and prune what you do not need. ### Regular cache management without nuking everything The cache is where Firefox stores downloaded page elements so it does not have to download them again. It speeds things up. But a bloated cache can slow things down. **The habit.** Once a month, go to Settings, Privacy and Security, Cookies and Site Data. Click Clear Data. Uncheck Cookies and Site Data so you do not lose your logins. Check Cached Web Content and clear it. Takes five seconds. ### When to refresh again Most people need to refresh Firefox once in the life of their computer. Maybe twice if they go through a heavy extension phase. But if you practice good browser hygiene, you might never need to refresh again. **The goal.** Keep your extension count under ten. Clear your cache monthly. Update Firefox when prompted. Do not install random add-ons from sketchy websites. Do those things and your browser stays fast indefinitely. ## Frequently Asked Questions ### Will I lose my history if I refresh? No. Firefox preserves your browsing history during a Refresh. All your visited pages, search terms, and form data remain intact. The only exception is if you manually check the Delete everything option during the process, which does clear history. ### Can I undo a Firefox refresh? Not directly. There is no undo button. But the Old Firefox Data folder on your desktop contains your entire previous profile. As long as you have not deleted that folder, you can restore your old setup by copying files from it back into the new profile. ### Does refresh delete malware? Sometimes. A Refresh removes most malicious extensions and corrupted profile data. But malware that installs itself at the system level, outside the Firefox profile, survives a refresh. For that kind of infection, you need a full antivirus scan or operating system reset. ### How is refresh different from clearing cookies? Clearing cookies only removes saved login information and site preferences. It does not touch extensions, settings, or profile data. A Refresh is much more thorough. It replaces your entire profile while keeping only bookmarks, passwords, history, and open tabs. ### Will Refresh fix a "Firefox is already running" error? Usually yes. That error happens when a background Firefox process gets stuck. A Refresh kills all processes and creates a fresh profile, which resolves the lock. But you can also try opening Task Manager, ending all Firefox processes manually, and restarting. ### How often should I refresh Firefox? There is no recommended schedule. Refresh only when you have a problem. Doing it proactively is unnecessary and wastes time reconfiguring your settings. Most users go years between refreshes.